Where:
N is the number of civilizations in our galaxy with which communication might be possible; and  R* is the average rate of star formation in our galaxy fp is the fraction of those stars that have planets ne is the average number of planets that can potentially support life per star that has planets fl is the fraction of the above that actually go on to develop life at some point fi is the fraction of the above that actually go on to develop intelligent life fc is the fraction of civilizations that develop a technology that releases detectable signs of their existence into space L is the length of time such civilizations release detectable signals into space. The tattoo above is a pictorial representation of the above seven factors. It starts out with a picture of galaxy and then each of the element of the equation is shown in a pictorial form.